Not a Nest, a Broom!

Q: In a pine tree in our back yard about twenty-five feet up there is a dense concentration of needles. I was wondering if it was some kind of nest?

A: It’s not a nest. It’s probably a pine broom. Brooming usually occurs at the tip of a limb that has been infected by fusiform rust, aphids, bacteria, or disease. The causal agent makes the terminal bud secrete hormones that cause multiple leaf buds to sprout in the same spot. This makes a dense growth that is easily seen as different from the rest of the tree. They can last on a tree for up to fifty years because of the increased photosynthesis occurring there. They are sought out by collectors because some brooms can result in dwarf plants that are quite attractive, like dwarf loblolly pine, Pinus taeda ‘Nana’ or Pinus taeda ‘Garden Treasures Gems’ dwarf pine. The downside of this dense growth is that it collects ice and snow and resists wind causing many to fall out of trees during the winter.

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Audrey Gilmore
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